D defs.my
Entry 1 sense Webster, 1913

Their

/thär/ · IPA /ðɛɚ/
01 pron. & a. The possessive case of the personal pronoun they; as, their houses; their country.
  1. 1.
    The possessive case of the personal pronoun they; as, their houses; their country.
    “Nothing but the name of zeal appears 'Twixt our best actions and the worst of theirs.” Denham.